In a move towards greater transparency in the justice system, ministers hope that judges could be filmed delivering verdicts and sentences.

No 10 has indicated that allowing filming in the court of appeal is being seen as a first step. Broadcasters will be given the right to film counsel and judges in appeal cases.

Ministers hope to extend filming to crown court cases. But broadcasters would only be allowed to film the judge during the delivery of the verdict and during sentencing. Defendants, witnesses and counsel on both sides would not be filmed.

A No 10 source said: "This is an important step in opening up the court process. Allowing the public to watch justice in action will help build trust in our judicial system. Hearing why verdicts have been given and watching the sentencing process will add to public confidence in the courts."

Ministers may be on a collision course with the judiciary. Lord Judge, the outgoing lord chief justice, said in January that he supported the principle of allowing cameras into court, but he drew a line at the filming of sentencing.

In his last appearance before the House of Lords constitution committee, he said: "I'm perfectly happy with cameras coming into court, provided their presence doesn't increase the risk that justice won't be done. [But] I'm very troubled about having cameras just swanning around the court."

On sentencing, he added: "Not sentencing, I take a very strong view about sentencing."

Judge cited difficulties in New Zealand. "Everybody thought that if you fixed the camera on the judge then it would be all right, but of course people can demonstrate during the sentencing remarks, so there are cheers and boos. We have to be very careful how it works."

The lord chief justice said judges would be given training for televised court of appeal hearings. He told the committee: "We will arrange for those judges who sit in these courts to have some training … the general idea is that it will start in October in the two courts of appeal."

Channel 4 will broadcast a documentary on 9 July about a notorious Scottish murder trial which includes scenes filmed in the high court in Edinburgh.

It is not the first time a Scottish trial has been televised, but it suggests, because consent had to be obtained from witnesses after their appearance, that the public is gradually becoming accustomed to the idea of cameras in courtrooms.

The televised case involves the murder of Arlene Fraser, a 33-year-old mother of two, who vanished without trace from her home in New Elgin, Moray, on 28 April 1998.

Her husband, Nat Fraser, was found guilty of her murder in May 2012 and sentenced to 17 years imprisonment. He had originally been convicted of the killing in 2003 but had the conviction overturned on appeal and was ordered to face a retrial.

Channel 4 was granted permission to film the hearing but had to seek witnesses' permission before their evidence could be broadcast. Most consented.The programme also contains interviews conducted with barristers, the judge, Arlene Fraser's family and others outside the courtroom. The film was shown to the judge and legal authorities in Scotland to check that it was accurate.